This invention relates to a fused monolithic ceramic capacitor package and more particularly to such a package containing an exothermically alloyable fuse.
Monolithic ceramic capacitors have at least two film electrodes that are buried within a dielectric ceramic body and that are spaced from each other by a thin layer of the ceramic material. When voltage is applied to the capacitor, an electric field is established within this thin ceramic layer which layer is typically from 0.0005 inch to 0.003 inch (0.0013 to 0.0075 cm.) thick. It ocasionally occurs that due to minor defects in this active dielectric layer small currents are established through the active dielectric layer which cause its temperature to rise. Leakage current tends to increase with increasing temperature and the whole body becomes progressively hotter. Ceramic capacitors thus tend to fail short.
In recent years it has become increasingly common practice to employ literally hundreds of monolithic ceramics on a single printed circuit board that also carries a large number of integrated circuit components, e.g. MOS-memory chips. The capacitors are typically connected directly across the low voltage power supply that has a large current capacity. Such boards are very expensive, e.g. $200-$400. When one of the many ceramic capacitors becomes defective, as described above, its temperature can easily exceed 1000.degree. C igniting and burning nearby components and often burning through the supporting board to the boards that may lie below.
It is accordingly an object of the present invention to provide a monolithic ceramic capacitor package that fails open prior to reaching destructive temperatures.